Plate structure for earth-boring tools, tools including plate structures and methods of forming such tools

ABSTRACT

Plate structures attachable to earth-boring tools comprise a disk including a circumferentially extending rim configured for attachment to an earth-boring tool. An aperture is formed through a portion of the disk and positioned radially interior from the rim. The aperture is configured to at least partially align with at least one junk slot of the earth-boring tool. Earth-boring tools comprising such plate structures, and methods of forming such earth-boring tools are also disclosed.

TECHNICAL FIELD

Embodiments of the invention relate generally to earth-boring tools and methods of forming earth-boring tools. More particularly, embodiments of the present invention relate to earth-boring tools comprising a plate structure and to methods of forming such tools.

BACKGROUND

Drilling wells for oil and gas production conventionally employs longitudinally extending sections, or so-called “strings,” of drill pipe to which, at one end, is secured a drill bit of a larger diameter. After a selected portion of the bore hole has been drilled, a string of tubular members of lesser diameter than the bore hole, known as casing, is placed in the bore hole. Subsequently, the annulus between the wall of the bore hole and the outside of the casing is filled with cement.

In drilling bore holes in subterranean earth formations by the rotary method, drill bits fitted with one or more cutters are conventionally employed. For example, rolling cutter or “rock bits” that include three rolling cutters in the form of so-called “cones,” or drag bits that include fixed cutters may be employed. So-called “hybrid” drill bits which employ, in combination, both fixed and rolling cutters are also known in the art. The drill bit is secured to the lower end of a drill string, which may be rotated from the surface using a rotary table or top drive, from within the bore hole using a down-hole motor or turbine, or using a combination of drive systems. The rolling cutters or fixed cutters mounted on the drill bit roll or slide on and across the exposed surface of the formation at the bottom of the bore hole as the bit is rotated, respectively crushing or shearing away the formation material. Many conventional drill bits also include fluid paths typically referred to as “junk slots” which extend longitudinally along an outer surface of the drill bit. The junk slots provide a pathway for cuttings, drill fluids, and other materials to travel between the drill bit and the borehole wall, upward from the bottom of the borehole and away from the drill bit. These junk slots conventionally extend to the proximal or trailing end of the drill bit.

BRIEF SUMMARY

Various embodiments of the present invention comprise a plate structure configured to be coupled with an earth-boring tool and providing a rim around an outer diameter of an earth-boring tool, including the junk slots. In one or more embodiments, the plate structure may comprise a disk comprising a circumferentially extending rim having a chamfered portion thereon and configured for attachment to an earth-boring tool. The disk may also include at least one aperture through a portion thereof, the at least one aperture being configured to at least partially circumferentially align with at least one junk slot of the earth-boring tool. The at least one aperture may be positioned radially interior from the rim.

Other embodiments of the invention comprise earth-boring tools including a plate structure. At least one embodiment may comprise a body comprising a face at a leading end thereof and structure at a trailing end thereof for connecting to a drill string. A disk may be coupled to the body encompassing a portion of the connecting structure. The disk may comprise a rim extending around an outer circumference thereof and at least one aperture through a surface of the disk. The at least one aperture may be positioned radially inward from the rim.

Other embodiments of the invention comprise methods for forming an earth-boring tool. One or more embodiments of such methods may comprise forming a body comprising a face at a leading end thereof. A disk may be formed comprising a rim extending around an outer circumference thereof. One or more apertures may be formed through a surface of the disk, the one or more apertures being positioned radially inward from the rim. The disk may be coupled to the body proximate a trailing end thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an isometric view of a plate structure 110 according to at least one embodiment of the invention.

FIG. 2 illustrates an isometric view of the plate structure of FIG. 1 including a plurality of gussets attached thereto.

FIG. 3 is an isometric view of an earth-boring tool according to at least one embodiment of the invention.

DETAILED DESCRIPTION

The illustrations presented herein are, in some instances, not actual views of any particular plate structure or drill bit, but are merely idealized representations which are employed to describe the present invention. Additionally, elements common between figures may retain the same numerical designation.

Various embodiments of the present invention are directed toward embodiments of a plate structure for an earth-boring tool. FIG. 1 illustrates an isometric view of a plate structure 110 according to at least one embodiment of the invention. The plate structure 110 comprises a disk 120 comprising a circumferentially extending rim 130. The rim 130 extends continuously through the circumference of the plate structure 110. The rim 130 may include a chamfer 150 thereon to aid in removing an earth-boring tool to which the plate structure 110 may be attached from a borehole. The chamfer 150 may reduce the chances that an earth-boring tool to which the plate structure 110 is coupled will get hung up on a ledge or other irregularity on the borehole wall or on other subterranean material when removing the earth-boring tool from the borehole. The angle of the chamfer 150 may be selected according to the specific application.

The disk 120 further includes at least one longitudinally extending aperture 140 through a portion thereof. The at least one aperture 140 is positioned radially interior from the rim 130 and is configured to at least partially align with at least one junk slot of an earth-boring tool to which the plate structure 110 may be attached. The disk 120 may be formed from a durable material such as those materials commonly known for use with conventional earth-boring tools. By way of example only, the disk 120 may be made from a metal or metal alloy such as steel, or a particle-matrix composite material. In some embodiments, the disk 120 may comprise an axially extending opening 160 through a central portion thereof, opening 160 sized and configured to fit around an outer surface of a shank or stem of an earth-boring tool.

In some embodiments, the plate structure 110 may comprise a plurality of ribs or gussets 170 attached to an upper, or trailing surface thereof (as the plate is oriented during use and with respect to the normal direction of drilling to form or enlarge a borehole). FIG. 2 illustrates an isometric view of the plate structure 110 of FIG. 1 including a plurality of gussets 170 attached thereto. According to some embodiments, the plurality of gussets 170 may also be coupled to a sleeve structure 180. The sleeve structure 180 may have another opening 190 sized similar to the opening 160 (FIG. 1) so as to fit around an outer surface of a shank or stem of an earth-boring tool. The gussets 170 may comprise a durable material similar to those used for the disk 120. By way of example and not limitation, the gussets 170 may comprise a metal or metal alloy, such as steel, as well as a particle matrix composite material. Gussets 170 provide reinforcement for, and enhanced rigidity to, plate structure 110.

The plate structure 110 is configured to be coupled to an earth-boring tool used in forming a borehole in subterranean features. Accordingly, additional embodiments of the present invention are directed to earth-boring tools which comprise a plate structure 110 according to various embodiments. FIG. 3 is an isometric view of an earth-boring tool 200 according to at least one embodiment of the invention. The earth-boring tool 200 comprises a body 210 having cutting structure 220 at a distal or leading portion thereof for engaging subterranean earth formations. The cutting structure 220 may include a plurality of cutting elements 240 over a portion thereof. Connecting structure 230 is coupled to the body at a proximal or trailing portion thereof for connecting to a drill string. Also coupled to the body 210 at a trailing end thereof is a plate structure 110 according to any of the embodiments described herein above or their equivalents.

In some embodiments, the earth-boring tool 200 may be configured as a pilot reamer assembly 250. In such a configuration, the body 210 may include a shaft 260 having a pilot bit 270 coupled thereto at the leading portion thereof, and a reamer assembly 280 trailing the pilot bit 240 at the trailing end of the body 210. The pilot bit 270 is shown as a roller cone bit, however, in other embodiments, the pilot bit 270 may comprise a drag bit or a hybrid bit, as are known generally to those of ordinary skill in the art. The reamer assembly 280 may comprise a plurality of bit legs or head sections 290 coupled to the outer periphery of the body 210, forming a plurality of junk slots 300 therebetween. Although the reamer assembly 280 is shown with cutters configured as roller cones, the reamer assembly 280 may also be configured with drag-type cutters or a combination of roller cone cutters and drag-type cutters. The plate structure 110 is coupled to the body 210 at the trailing end thereof.

The plate structure 110 is aligned so that the apertures 140 are at least partially circumferentially aligned with the junk slots 300. Such a circumferential alignment may allow cuttings, drilling fluid, etc. to pass upward and away from the body 210 in a borehole in the annulus formed between the drill string to which earth-boring tool 200 is attached, and the wall of the borehole. With the rim 130 extending continuously about the circumference of the plate structure 110, the cuttings, drilling fluid, etc. passing through the apertures 140 will pass radially inside with respect to the rim 130. The rim 130, therefore, may provide a continuous surface, including at those regions where the junk slots 300 are located, to aid in removing the earth-boring tool 200 from a borehole, among other things. As discussed above, the rim 130 may include a chamfer which may reduce the chances that the earth-boring tool 200 will get hung up on a ledge or other irregularity on the borehole wall or on other subterranean material when being removed from the borehole.

The plate structure 110 may comprise an outer diameter substantially equivalent to the outermost diameter of the body 210. In other embodiments, the sleeve structure 220 may comprise an outer diameter which is less than the outermost diameter of the body 210. Such a configuration may avoid excessive wear to the outermost portion of the plate structure 110. In some embodiments, the plate structure 110 may include wear resistant coatings and/or inserts as known in the art to inhibit excessive wear thereto. By way of example and not limitation, the wear resistant coatings and/or inserts may include hardfacing material, tungsten carbide inserts, natural or synthetic diamonds, or a combination thereof.

Further embodiments of the present invention are directed to methods of forming earth-boring tools which comprise a body 210 and a plate structure 110 according to various embodiments. A body 210 may be formed and coupled to connecting structure 230. The connecting structure 230 may be formed as a shank comprising a trailing portion including structure comprising an American Petroleum Institute (API) thread connection for attachment to a drill string. The connecting structure 230 may be formed separate from the body 210 in some embodiments and may be attached to the body 210 by welding or otherwise affixing the connecting structure 230 to the body 210. The weld may be formed by any conventional welding process as is known to those of ordinary skill in the art. Other methods of securing connecting structure 230 to a bit body are also known, and may be employed. In other embodiments, the connecting structure 230 and the body 210 are formed as a single, unitary piece. Cutting structure 220 may be formed on the body 210 at a leading portion thereof and may include cutting elements conventionally used for earth-boring tools.

A plate structure 110 is formed comprising a disk 120 including a rim 130 extending continuously through the circumference of the disk 120. In some embodiments, the body 210 as well as the plate structure 110 may be formed as an integral structure. In such embodiments, the body 210 and the plate structure 110 may be formed simultaneously and of a similar material. In other embodiments, the body 210 and the plate structure 110 may each be formed separately as individual pieces which are subsequently joined. In such embodiments, the plate structure 110 is secured to the body 210. By way of example and not limitation, in some embodiments the opening 160 (FIG. 1), as well as the another opening 190 (FIG.2) when present, may comprise a diameter configured to create an interference fit with the connecting structure 230 of the body 210. In some embodiments, the plate structure 110 may be welded to the body 210 as well as to the connecting structure 230.

In embodiments comprising gussets 170, the gussets 170 may be formed separately from the body 210 and disk 120. The gussets 170 may be formed from a flat plate, the gussets 170 being machined, punched or cut from the flat plate material or otherwise formed according to conventional methods. In some embodiments, the gussets 170 may be attached directly to the disk 120. In other embodiments, the gussets 170 may be attached to a sleeve structure 180, the sleeve structure 180 with the gussets 170 being attached to the disk 120. In some embodiments, the another opening 190 (FIG. 2) of the sleeve structure 180 may comprise a diameter configured to create an interference fit with the connecting structure 230 of the body 210. The gussets 170 and sleeve structure 180 may also be welded to the disk 120, the connecting structure 230, or both.

The body 210 as well as the plate structure 110, including any gussets 170, may comprise a metal or metal alloy, such as steel, or a particle-matrix composite material. In the case of a particle-matrix composite material, the body 210 and/or the plate structure 110 may be formed by conventional infiltration methods (in which hard particles (e.g., tungsten carbide) are infiltrated by a molten liquid metal matrix material (e.g., a copper based alloy) within a refractory mold), as well as by newer methods generally involving pressing a powder mixture to form a green powder compact, and sintering the green powder compact to form a body 210 and/or plate structure 110. The green powder compact may be machined as necessary or desired prior to sintering using conventional machining techniques like those used to form steel bodies or steel plate structures. Furthermore, additional machining processes may be performed after sintering the green powder compact to a partially sintered brown state, or after sintering the green powder compact to a desired final density.

One or more wear resistant inserts and/or a wear resistant coatings may be disposed on a radially outer surface of the rim 130 of the plate structure 110, as well as the plurality of gussets 170 if present. Wear resistant inserts may be attached to the plate structure 110 using a bonding material such as an adhesive or, more typically, a braze alloy may be used to secure the wear resistant inserts to the plate structure 110. A wear resistant coating may comprise a hardfacing or similar material. The wear resistant coating may be disposed over the outer surfaces of the rim 130, the disk 120, as well as over surfaces of the gussets 170 when present. The wear resistant coating may be disposed employing a conventional welding process such as oxy-acetylene, MIG, TIG, SMA, SCA, PTA, etc.

While the present invention has been described herein in relation to embodiments of earth-boring pilot reamers that include roller cone cutters, other types of earth-boring tools such as, for example, core bits, eccentric bits, bicenter bits, reamers, mills, fixed-cutter rotary drill bits, and other such structures known in the art may incorporate embodiments of the present invention and may be formed by methods according to embodiments of the present invention, and, as used herein, the term “body” encompasses bodies of earth-boring rotary drill bits, as well as bodies of other earth-boring tools including, but not limited to, core bits, eccentric bits, bicenter bits, reamers, mills, roller cone bits, as well as other drilling and downhole tools.

While certain embodiments have been described and shown in the accompanying drawings, such embodiments are merely illustrative and not restrictive of the scope of the invention, and this invention is not limited to the specific constructions and arrangements shown and described, since various other additions and modifications to, and deletions from, the described embodiments will be apparent to one of ordinary skill in the art. Thus, the scope of the invention is only limited by the literal language, and legal equivalents, of the claims which follow. 

1. A plate structure attachable to an earth-boring tool, comprising: a disk comprising a circumferentially extending rim configured for attachment to an earth-boring tool; and an aperture through a portion of the disk configured to at least partially circumferentially align with at least one junk slot of an earth-boring tool, the aperture being positioned radially interior from the rim.
 2. The plate structure of claim 1, wherein the rim has a chamfered portion thereon.
 3. The plate structure of claim 1, wherein the disk comprises a material selected from the group consisting of a metal, a metal alloy, and a particle-matrix composite.
 4. The plate structure of claim 1, further comprising at least one of a wear-resistant insert and a wear-resistant coating on at least an outer surface of the rim.
 5. The plate structure of claim 1, wherein the aperture comprises a plurality of apertures through a portion of the disk, each aperture of the plurality of apertures configured to at least partially align with at least a portion of at least one junk slot.
 6. The plate structure of claim 1, further comprising a plurality of gussets attached to a trailing surface of the disk.
 7. The plate structure of claim 6 wherein at least the rim and the plurality of gussets comprise a hardfacing material over at least a portion of a surface thereof.
 8. An earth-boring tool, comprising: a body comprising a face at a leading end thereof and structure at a trailing end thereof for connecting to a drill string; a disk encompassing a portion of the structure at the trailing end and comprising a rim extending around an outer circumference thereof and at least one aperture through a surface of the disk and positioned radially inward from the rim.
 9. The earth-boring tool of claim 8, wherein the body comprises a longitudinally extending shaft, and further comprising: a pilot bit coupled to a leading portion of the longitudinally extending shaft; and a reamer assembly coupled to the body and trailing the pilot bit.
 10. The earth-boring tool of claim 9, wherein the pilot bit is configured as a roller cone bit, a drag bit, or a hybrid bit.
 11. The earth-boring tool of claim 9, wherein the reamer assembly comprises a plurality of bit legs coupled to an outer periphery of the body and forming a plurality of junk slots therebetween.
 12. The earth-boring tool of claim 11, wherein the disk comprises a plurality of apertures and wherein each aperture of the plurality of apertures is at least partially circumferentially aligned with at least a portion of at least one junk slot of the plurality of junk slots.
 13. The earth-boring tool of claim 8, wherein the rim comprises a chamfered portion thereon.
 14. The earth-boring tool of claim 8, further comprising at least one of a wear-resistant insert and a wear-resistant coating on at least an outer surface of the rim.
 15. The earth-boring tool of claim 8, wherein the disk and the body comprise an integral structure.
 16. The earth-boring tool of claim 8, further comprising a plurality of gussets attached to a trailing surface of the disk.
 17. The earth-boring tool of claim 8, further comprising a sleeve structure, wherein the plurality of gussets is coupled to the sleeve structure.
 18. A method of forming an earth-boring tool, comprising: forming a disk comprising a rim extending around an outer circumference thereof; forming at least one aperture through a surface of the disk and positioned radially inward from the rim; forming a body comprising a face at a leading end thereof; and coupling the disk to the body, wherein a connecting structure protrudes from the body and extends through the disk radially inwardly of the at least one aperture.
 19. The method of claim 18, wherein forming at least one of the body and the disk comprises: providing a powder mixture; pressing the powder mixture to form a green powder compact; and at least partially sintering the green powder compact.
 20. The method of claim 18, wherein forming the disk comprises forming the disk integrally and substantially simultaneously with forming the body.
 21. The method of claim 18, wherein forming the disk comprises forming the disk separate from the body and coupling the disk to the body.
 22. The method of claim 18, further comprising forming a chamfered portion on an outer surface of the rim.
 23. The method of claim 18, further comprising disposing at least one of a wear-resistant insert and a wear-resistant coating on at least an outer surface of the rim.
 24. The method of claim 18, further comprising: forming a plurality of gussets; and securing the plurality of gussets to the disk.
 25. The method of claim 24, further comprising securing the plurality of gussets to a sleeve protruding axially from the disk.
 26. The method of claim 18, further comprising forming a plurality of gussets coupled with the disk substantially simultaneously with the formation thereof.
 27. The method of claim 26, further comprising forming a sleeve axially protruding from disk and secured to the disk and to the sleeve substantially simultaneously with forming the disk and the plurality of gussets.
 28. The method of claim 18, further comprising substantially circumferentially aligning a junk slot associated with the body with the at least one aperture. 